短蛸产蛋白酶菌的鉴定、发酵条件优化及酶学性质

Identification of Protease-producing Strain from Octopus ocellatus Intestine, Optimization of Fermentation Conditions and Enzymatic Properties

采用生理生化特征、16S r DNA分析的方法对分离自短蛸胃肠道产蛋白酶菌株S-3进行鉴定。通过单因素试验、正交设计优化发酵产生蛋白酶条件,对产蛋白酶的粗酶性质进行研究。结果表明,菌株S-3与灿烂弧菌最相似,在以淀粉0.5%,蛋白胨0.5%,酵母膏0.1%,磷酸高铁0.1%为最佳培养基,初始p H 8.0,接种量7%,20℃发酵3.5 d时产蛋白酶活性最高,即121.1 U/m L。所产粗蛋白酶最适作用p H 9.0,最佳作用温度50℃,具有较高的热稳定性及p H稳定性,这为蛋白酶的工业应用提供了理论依据。

A protease-producing strain S-3 have been isolated from the gastrointestinal tract of Octopus ocellatus. Based on biochemical, physiological tests, and analysis of 16S rDNA sequence, the strain was mostly similar with vibrio splendidus. The optimal fermentation conditions with highest protease activity by using orthogonal methods and single-factor experiments were as follows：1.0% soluble starch, 0.1% yeast, 0.5% peptone, and 0.1% ferric phosphate with initial pH 8.0, inoculums 7% at 20℃ for about 3.5 d. The crude alkaline protease showed optimum activity at pH 9.0 and it was highly stable over a wide range pH from 7.0 to 10.0. The optimum temperature of activity was 50 ℃ and only about 16% of the initial activity was lost after an incubation period of 60 min at 50 ℃.